Writing in The Daily Telegraph, he said the eventual approval by the Home Office for medicinal cannabis oil to be used to treat epileptic youngster Billy Caldwell was evidence that a hard-line stance on the drug had become "inappropriate, ineffective and utterly out of date".

He said it was time for the government to "embrace a decisive change", adding: "Can British Conservatives be as bold as Canadian Liberals? We ought to be."

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Video:'I tried cannabis in the US,' says MP

While a Sky Data poll has found most Britons agree that cannabis should be made legal for medicinal purposes, it is a far more even split when it comes to recreational use - with 41% in favour and 40% against.